Skilled Soft Text File Encryptor

The problem was protecting notepad text files from prying eyes as it doesn't come with password protection as its counterparts e.g. Microsoft Word

Develop a windows application that does the obfuscation to avoid complexity or need to remember anything by users except where application is. 

The application was a simple standalone one that runs on windows and all you do is choose a text file then say whether to encrypt or decrypt.